1. Field of the Invention
The present invention relates to a radiographic tomography apparatus, which is capable of detecting body motion of an examinee, particularly in cases where the examinee should be kept still while a radiographic image of the examinee is being captured.
2. Description of the Related Art
In a radiographic imaging process, a satisfactory radiographic image of an examinee may not be captured if the body of the examinee moves too much, or if the region of the examinee that is to be imaged significantly changes in position. There have been proposed radiographic tomography apparatus, which are designed to reduce the effect that body motions of the examinee have on a radiographic image (see U.S. Patent Application Publication No. 2006/0074300 A1, and U.S. Patent Application Publication No. 2006/0235295 A1).
According to U.S. Patent Application Publication No. 2006/0074300 A1, electrodes are attached to the chest of a patient (see paragraph [0020] of U.S. Patent Application Publication No. 2006/0074300 A1), and a radiographic image of the patient is enlarged or reduced, depending on the breathing characteristic of the patient corresponding to impedance changes detected through the electrodes, thereby reducing image blurs (see paragraph [0024] of U.S. Patent Application Publication No. 2006/0074300 A1).
According to U.S. Patent Application Publication No. 2006/0235295 A1, an ECG probe is attached to a patient (see paragraph [0025] of U.S. Patent Application Publication No. 2006/0235295 A1), whereby the motion of the heart of the patient is calculated from a CT image of the patient, and a PET image or the like of the patient is corrected based on the calculated motion (see paragraph [0028] of U.S. Patent Application Publication No. 2006/0235295 A1).
There has also been proposed a radiographic tomography apparatus using tomosynthesis for acquiring three-dimensional image information in one tomographic imaging process (see U.S. Pat. No. 7,127,028 B2). The radiographic tomography apparatus disclosed in U.S. Patent Application Publication No. 2006/0074300 A1 and U.S. Patent Application Publication No. 2006/0235295 A1 detect only body motions caused by heart beating and breathing, but do not take into account other body motions of the patient. As a result, if the patient produces body motions other than body motions caused by the patient's heart beat and breathing, then the measurement accuracy of the radiographic tomography apparatus tends to be lowered. U.S. Pat. No. 7,127,028 B2, however, also fails to reveal anything concerning such other body motions.